What is the Number of Turns in the Secondary Coil of a Transformer?

[chikis]

Homework Statement

Hello everybody, am confronted with this question:
A transformer with 5500 turns in its primary is used between a 240V a.c supply and a 120V kettle. Calculate the number of turns in the secondary.

Homework Equations

The equation Es/Ep = Ns/Np can be applied in solving the problem.
Where Es = e.m.f of secondry. Ep = e.m.f of primary, Ns = number of turns in secondary coil, Np number of turns in primary coil

The Attempt at a Solution

Using the formula:
Es/Ep = Ns/Np
Where Np = 5500turns
Ns = ? becuase am required to calculate for it.
For Es and Ep, I don't know the value to substitute in for Es and Ep respectively. Whether is the 240V or 120V. I don't know between 240V and 120V the one that is Ep or Es respectively.
I can't go further with the calculation since am unable to substitute in the values into the equation correctly. Can sombody help me here please?

 

[tiny-tim]

hi chikis!

For Es and Ep, … I don't know between 240V and 120V the one that is Ep or Es respectively.

the coil with the electricity source going through it is always the primary

 

[chikis]

hi chikis!


the coil with the electricity source going through it is always the primary

Thank you very much tiny-tim,
that answer have solved my problem. I will work the problem and forward the working in for all to view. Thank you once again, am very greatful.

 

[chikis]

hi chikis!


the coil with the electricity source going through it is always the primary

Thank you very much tiny-tim,
that answer have solved my problem. I will work the problem and forward the working in for all to view. Thank you once again, am very greatful.

 

[chikis]

Here is the working:
E_p/E_s=N_p/N_s
=240/120=5500/N_s
:.
N_s=5500*120/240
=2750
My thanks goes to tim-tim who has contributed immensly to this thread.

 

[tiny-tim]

N_s=5500*120/240
=2750

yes that's fine!

 

[chikis]

yes that's fine!

Thanks for that compliment.